1. Field
The present application relates generally to wireless communications, and more specifically to methods and systems for facilitating transmit diversity for communications.
2. Background
Wireless communication systems are widely deployed to provide various types of communication content such as voice, data, and so on. These systems may be multiple-access systems capable of supporting communication with multiple users by sharing the available system resources (e.g., bandwidth and transmit power). Examples of such multiple-access systems include code division multiple access (CDMA) systems, time division multiple access (TDMA) systems, frequency division multiple access (FDMA) systems, 3GPP Long Term Evolution (LTE) systems, and orthogonal frequency division multiple access (OFDMA) systems.
Generally, a wireless multiple-access communication system can simultaneously support communication for multiple wireless terminals. Each terminal communicates with one or more base stations via transmissions on the forward and reverse links. The forward link (or downlink) refers to the communication link from the base stations to the terminals, and the reverse link (or uplink) refers to the communication link from the terminals to the base stations. This communication link may be established via a single-in-single-out, multiple-in-signal-out or a multiple-in-multiple-out (MIMO) system.
Transmit diversity schemes may be used for enhancing communication reliability in a wireless multiple-access communication system. One problem with transmit diversity is interference among transmitters that transmit on common resources. For example, in a third generation partnership project (3GPP) long term evolution (LTE) network, only a single resource is allocated to data transmitted on a physical uplink control channel (PUCCH). As such, employing different time or frequency resources is not available for LTE PUCCH data. Likewise, other systems specify control, traffic, pilot, etc., data with a single resource, negating orthogonal resource transmissions. Thus, improved apparatus and methods for facilitating transmit diversity schemes are desired.